When Peter Mandelson said the Labour Party was "intensely relaxed" about people becoming filthy rich (as long as they pay their taxes) he was saying something far more fundamental than he maybe realised.

Lord Mandelson made the comments in 1998, an era when income growth was 5.6% and inflation (the consumer prices index) was 1.4%.

Real incomes were rising by a healthy 4.2%.

Being relaxed about the rich was far easier when your income was also rising.

The picture is now very different.

Today's wage growth figures from the Office for National Statistics show a sharp decline to 2.3%, down from 2.6% the previous month.

Inflation is now at 1.8%, up from 1.6%.

Real income growth - admittedly on a slightly different measure from 1998 - is now running at 0.6%.

Of course, these are one month's figures but the trend is clear.

Inflation is rising, mainly a function of a weaker currency leading to higher import costs for things like food and fuel.

And wage growth is slowing despite a robust employment market.

As Matthew Taylor, the head of the government review into employment, told me, Britain is good at creating jobs and not so good at creating well-paid jobs.

With economic growth predicted to slow next year, employees are still fighting shy of demanding significant pay increases.

Productivity is still stubbornly low, which means that wealth creation per hour worked is limited.

And in the public sector the pay freeze continues.

This is the Prime Minister's significant and growing headache.

She made an economy "that works for everyone" the cornerstone of her government's offer to the electorate.

Falling real incomes do not fit comfortably with that narrative.

And if the incomes squeeze translates into falling consumer confidence, then the main driver of the better than expected economic news since the referendum could turn more negative.

As Torsten Bell of the Resolution Foundation said: "Our pay recovery is now rapidly ending.

"Pay growth is already zero on single month data and we expect 3 month growth to be just 0.2% next month."

Put aside Brexit, the Scottish referendum, Donald Trump - when it comes to the economy, falling incomes is becoming the real and present political danger.